Non-metallic engine case inlet compression seal for a gas turbine engine

ABSTRACT

A non-metallic engine case inlet compression seal for a gas turbine engine includes a non-metallic longitudinal leg section that extends from the non-metallic arcuate interface section and a non-metallic mount flange section that extends from the longitudinal leg section.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of provisional application Ser. No.62/084,603, filed Nov. 26, 2014.

BACKGROUND

The present disclosure relates to a gas turbine engine and, moreparticularly, to a non-metallic engine case inlet compression sealtherefor.

Gas turbine engines, such as those which power modern military aircraft,include a compressor section to pressurize a supply of air, a combustorsection to burn a hydrocarbon fuel in the presence of the pressurizedair, and a turbine section to extract energy from the resultantcombustion gases and generate thrust. Downstream of the turbine section,an augmentor section, or “afterburner”, is operable to selectivelyincrease thrust. The increase in thrust is produced when fuel isinjected into the core gases downstream of the turbine section andburned with the oxygen contained therein to generate a second combustionthat is then passed through a variable area nozzle system.

In gas turbine powered aircraft, especially military aircraft, locationof the gas turbine engine within the airframe reduces drag andsignature. The internal engine location, however, necessarily requiresairflow to be routed through an intake duct in the airframe to theengine. The intake duct is typically integrated with the airframe andinterfaces with the engine case inlet via a compression seal interfaceto effectively communicate airflow to the engine. The compression sealinterface often includes a K-seal mounted to the airframe and a J-sealmounted to the engine. Typically, the K-seal is non-metallic and theJ-seal are manufactured of a titanium material. Although effective, theJ-seal may be relatively difficult to manufacture and may be susceptibleto cycle fatigue.

SUMMARY

A non-metallic engine case inlet compression seal for a gas turbineengine, according to one disclosed non-limiting embodiment of thepresent disclosure includes a non-metallic arcuate interface section; anon-metallic longitudinal leg section that extends from the non-metallicarcuate interface section; and a non-metallic mount flange section thatextends from the longitudinal leg section.

A further embodiment of the present disclosure includes, wherein thenon-metallic arcuate interface section has a durometer different than adurometer of the non-metallic longitudinal leg section.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the non-metallic arcuate interface sectionhas a durometer different than a durometer of the non-metallic mountflange section.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the non-metallic longitudinal leg sectionhas a durometer different than a durometer of the non-metallic mountflange section.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein each of the non-metallic arcuate interfacesection, the non-metallic longitudinal leg section, and the non-metallicmount flange section have a different durometer.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein each of the non-metallic arcuate interfacesection, the non-metallic longitudinal leg section, and the non-metallicmount flange section are integral.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein each of the non-metallic arcuate interfacesection, the non-metallic longitudinal leg section, and the non-metallicmount flange section are integral.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein each of the non-metallic arcuate interfacesection, the non-metallic longitudinal leg section, and the non-metallicmount flange section are manufactured of a silicone rubber.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the non-metallic arcuate interface section,the non-metallic longitudinal leg section, and the non-metallic mountflange section form a circular “J” seal.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the non-metallic mount flange has amultitude of apertures.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein at least one of the non-metallic arcuateinterface section, the non-metallic longitudinal leg section, and thenon-metallic mount flange section includes fiber reinforcement.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the fiber reinforcement includes an aramidmaterial.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, a fiber reinforcement that impregnates at least oneof the non-metallic arcuate interface section, the non-metalliclongitudinal leg section, and the non-metallic mount flange section.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, a fiber reinforcement bonded to an outer surface ofat least one of the non-metallic arcuate interface section, thenon-metallic longitudinal leg section, and the non-metallic mount flangesection.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the non-metallic arcuate interface sectionforms a bulb.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, an interface to the bulb to receive air topressurize the bulb.

A non-metallic engine case inlet compression seal for a gas turbineengine, according to another disclosed non-limiting embodiment of thepresent disclosure includes an non-metallic arcuate interface section,the non-metallic arcuate interface section forms a bulb; and aninterface to the bulb to receive and air to pressurize the bulb.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, a non-metallic longitudinal leg section thatextends from the non-metallic arcuate interface section.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes a non-metallic mount flange section that extendsfrom the longitudinal leg section.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein each of the non-metallic arcuate interfacesection, the non-metallic longitudinal leg section, and the non-metallicmount flange section are manufactured of a silicone rubber.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features will become apparent to those skilled in the art fromthe following detailed description of the disclosed non-limitingembodiment. The drawings that accompany the detailed description can bebriefly described as follows:

FIG. 1 is a general schematic view of an example gas turbine engine witha nozzle section according to one disclosed non-limiting embodiment;

FIG. 2 is a phantom view of an airframe illustrating a non-metallicengine case inlet compression seal between an aircraft intake duct andan engine case inlet of the gas turbine engine;

FIG. 3 is an exposed sectional of the non-metallic engine case inletcompression seal mounted to an engine case;

FIG. 4 is a partial perspective view of the non-metallic engine caseinlet compression seal according to one disclosed non-limitingembodiment;

FIG. 5 is a sectional view of the non-metallic engine case inletcompression seal according to one disclosed non-limiting embodiment;

FIG. 6 is a sectional view of the non-metallic engine case inletcompression seal according to one disclosed non-limiting embodiment;

FIG. 7 is a sectional view of the non-metallic engine case inletcompression seal according to one disclosed non-limiting embodiment; and

FIG. 8 is a sectional view of the non-metallic engine case inletcompression seal according to one disclosed non-limiting embodiment.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool, low-bypass,augmented turbofan that generally incorporates a fan section 22, acompressor section 24, a combustor section 26, a turbine section 28, anaugmenter section 30, a duct section 32, and a non-metallic engine caseinlet compression seal 34 along a central longitudinal engine axis A.Although depicted as an augmented low bypass turbofan in the disclosednon-limiting embodiment, it should be appreciated that the conceptsdescribed herein are applicable to other gas turbine engines includingnon-augmented engines, geared architecture engines, direct driveturbofans, turbojet, turboshaft, multi-stream variable cycle, and otherengine architectures with a nozzle system.

An outer case structure 36 and an inner case structure 38 define agenerally annular secondary airflow path 40 around a core airflow path42. Various structures and modules may define the outer case structure36 and the inner case structure 38 which essentially define anexoskeleton to support rotational hardware therein. Air that enters thefan section 22 is divided between core airflow through the core airflowpath 42, and secondary airflow through the secondary airflow path 40.The core airflow passes through the combustor section 26, the turbinesection 28, then the augmentor section 30, where fuel may be selectivelyinjected and burned to generate additional thrust through thenon-metallic engine case inlet compression seal 34.

The secondary airflow may be utilized for a multitude of purposes toinclude, for example, cooling, pressurization and variable cycleoperations. The secondary airflow as defined herein is any airflowdifferent from the core airflow. The secondary airflow may ultimately beat least partially injected into the core airflow path 42 adjacent tothe duct section 32 and the non-metallic engine case inlet compressionseal 34. It should be appreciated that additional airflow streams mayadditionally be provided.

With reference to FIG. 2, the engine 20 is removably located within anairframe 50 (illustrated schematically). It should be appreciated thatvarious airframe 50 configurations will benefit herefrom. The airframe50 generally includes an engine bulkhead 52, an engine bay 54, an inlet56, and an intake duct 58. The intake duct 58 is integrated within, orforms a portion of, the airframe 50. The bulkhead 52 is locatedgenerally between the intake duct 58 and the engine bay 54.

With reference to FIG. 3, the engine 20, which is situated in the enginebay 54, is coupled to the intake duct 58 by a compression interfaceformed by a bulkhead seal 60 and a non-metallic engine case inletcompression seal 70 (FIG. 4). The bulkhead seal 60, such as a K-seal, ismounted to the bulkhead 52. The non-metallic engine case inletcompression seal 70, such as J-seal, is mounted to the outer casestructure 36. Thus, the engine 20 is sealed with the intake duct 58through the compression interface formed by the J-seal and the K-sealsuch that air is routed from the inlet 56 to the engine 20. For clarity,only a circumferential portion of the non-metallic engine case inletcompression seal 70 and the bulkhead seal 60 are shown. Normally, thenon-metallic engine case inlet compression seal 70 and the bulkhead seal60 entail full 360° rings, of either a single piece or ring segments.

The bulkhead seal 60 generally includes an inner leg 62, an outer leg64, and a mount flange 66. The inner leg 62 and the outer leg 64 atleast partially receive the non-metallic engine case inlet compressionseal 70 therebetween. The mount flange 66 permits attachment of thebulkhead seal 60 to the engine bulkhead 52. The bulkhead seal 60 istypically manufactured of an alloy such as titanium. It should beappreciated that various configurations may be provided.

With reference to FIG. 5, the non-metallic engine case inlet compressionseal 70 generally includes a non-metallic arcuate interface section 72,a non-metallic longitudinal leg section 74, and a non-metallic mountflange section 76. The non-metallic arcuate interface section 72 extendsfrom the non-metallic longitudinal leg section 74 to, in this example,form a generally “J” shape. The non-metallic mount flange section 76extends transversely from the non-metallic longitudinal leg section 74and includes a multitude of apertures 78. Each of the apertures 78receives a fastener 80 to mount the non-metallic engine case inletcompression seal 70 to the outer case structure 36 forward of the fansection 22. In this embodiment, the non-metallic engine case inletcompression seal 70 extends from the outer case structure 36 from theforward circumferential edge of the fan section 22 forward of an enginemount 82 (FIG. 3).

The non-metallic longitudinal leg section 74 may include a steppedsurface 84 that abuts a forward edge 86 of the outer case structure 36.Alternatively, the non-metallic longitudinal leg section 74 may form anaperture 88 (FIG. 6) at least partially through the stepped surface 84to receive a sensor 90 (illustrated schematically) such as a pressuresensor therein. The aperture 88, in this example, is continuous with thestepped surface 84.

The non-metallic engine case inlet compression seal 70 is manufacturedof a non-metallic material 100 such as silicone rubber formed, orextruded, to shape. It should be appreciated that various non-metallicmaterials may be utilized. The cross section and stiffness of thenon-metallic engine case inlet compression seal 70 is arranged to sealthe interface irrespective of relative motion between the airframe 50and the engine 20 such as is typical during maneuvering flight.

With reference to FIG. 7, in another disclosed non-limiting embodiment,the material 100 may include fiber reinforcement 110 with, for example,meta-aramid material fibers. The fiber reinforcement 110 may be utilizedto impregnate the non-metallic engine case inlet compression seal 70 toprovide strength and stiffness, alternatively, or in addition thereto,fiber reinforcement 120 may, be bonded to the outer surfaces of thenon-metallic engine case inlet compression seal 70 to provide strengthand durability. In one example, the fiber reinforcement 110 may belocated to directly contact upon the bulkhead seal 60 for strength,reduced friction, etc. In another example, the fiber reinforcement 110may be located as reinforcement for strength or increased bond strength.It should be appreciated that beyond mechanical retention of fastenersthe non-metallic engine case inlet compression seal 70 may also beretained via bonding. The material 100 may further include variouscoatings to, for example, increase lubricity, heat resistance, etc.

In another disclosed non-limiting embodiment, one or more of thenon-metallic arcuate interface section 72, the non-metallic longitudinalleg section 74, and the non-metallic mount flange section 76, may bemanufactured of different non-metallic materials. In one example, thenon-metallic mount flange section 76 may be manufactured of a materialthat has a relatively higher durometer than that of the non-metallicarcuate interface section 72, yet be integrated thereto such as viaco-molding, over-molding, or other such manufacturing process. Inanother disclosed non-limiting embodiment, the non-metallic longitudinalleg section 74 may be manufactured of a relatively rigid non-metallicmaterial, or include an insert 130 thereof.

With reference to FIG. 8, in another disclosed non-limiting embodiment,an non-metallic engine case inlet compression seal 70A may include anon-metallic arcuate interface section 72A that forms a bulb 140. Thebulb 140 may include an interface 142 to receive air from an airpressure source to pressurize a pressurization region 144 formed by thebulb 140. The air pressure source, for example, may be secondary airflowsourced from the secondary airflow path 40 (FIG. 1). The bulb 140 isthereby pressurized to facilitate formation of a conforming compressionseal that readily provide an increased contact surface with the bulkheadseal 60. That is, the pressurization region 144 thereby drives the bulb140 into the bulkhead seal 60 to increase contact therewith.

The non-metallic engine case inlet compression seal is relativelyuncomplicated to manufacture yet provides for relatively complexgeometries that may include one or more pressurized regions. Thenon-metallic material also provides for considerable design options suchas shape, durometer, coatings, reinforcement, and/or pressurization. Thenon-metallic engine case inlet compression seal readily toleratesapplication temperatures and provides flexibility of design for uniqueproperties at various sections such as rigid and stiff at fasteninglocation, flexible and resilient at a seal interface, and/or rigid wherepressure sensors or other features may be installed. The non-metallicengine case inlet compression seal is also relatively insensitive toshipping and handling conditions. The non-metallic engine case inletcompression seal also avoids the necessity of metallic seal stop crackdrilling may be readily mended.

The use of the terms “a,” “an,” “the,” and similar references in thecontext of description (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or specifically contradicted bycontext. The modifier “about” used in connection with a quantity isinclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the particular quantity). All ranges disclosed herein areinclusive of the endpoints, and the endpoints are independentlycombinable with each other. It should be appreciated that relativepositional terms such as “forward,” “aft,” “upper,” “lower,” “above,”“below,” and the like are with reference to normal operational attitudeand should not be considered otherwise limiting.

Although the different non-limiting embodiments have specificillustrated components, the embodiments of this invention are notlimited to those particular combinations. It is possible to use some ofthe components or features from any of the non-limiting embodiments incombination with features or components from any of the othernon-limiting embodiments.

It should be appreciated that like reference numerals identifycorresponding or similar elements throughout the several drawings. Itshould also be appreciated that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom.

Although particular step sequences are shown, described, and claimed, itshould be understood that steps may be performed in any order, separatedor combined unless otherwise indicated and will still benefit from thepresent disclosure.

The foregoing description is exemplary rather than defined by thelimitations within. Various non-limiting embodiments are disclosedherein, however, one of ordinary skill in the art would recognize thatvarious modifications and variations in light of the above teachingswill fall within the scope of the appended claims. It is therefore to beunderstood that within the scope of the appended claims, the disclosuremay be practiced other than as specifically described. For that reasonthe appended claims should be studied to determine true scope andcontent.

What is claimed:
 1. A J-shaped non-metallic engine case inletcompression seal for a gas turbine engine to form a compressioninterface with an airframe bulkhead, comprising: a non-metallic arcuateinterface section; a non-metallic longitudinal leg section that extendsfrom said non-metallic arcuate interface section, said non-metalliclongitudinal leg section configured to be at least partially radiallysupported on an outer case structure of the gas turbine engine, saidnon-metallic longitudinal leg section comprises a radially inwardlyprojecting stepped surface configured for positioning immediatelyaxially adjacent to a forward circumferential edge of said outer casestructure, said non-metallic longitudinal leg section configured forpositioning on top of the outer case structure; and a non-metallic mountflange section that extends transversely from said longitudinal legsection, said non-metallic mount flange having a multitude of aperturesto mount said non-metallic engine case inlet compression seal to saidouter case structure of said gas turbine engine.
 2. The non-metallicengine case inlet compression seal as recited in claim 1, wherein saidnon-metallic arcuate interface section has a durometer hardnessdifferent than a durometer hardness of said non-metallic longitudinalleg section.
 3. The non-metallic engine case inlet compression seal asrecited in claim 1, wherein said non-metallic arcuate interface sectionhas a durometer hardness different than a durometer hardness of saidnon-metallic mount flange section.
 4. The non-metallic engine case inletcompression seal as recited in claim 1, wherein said non-metalliclongitudinal leg section has a durometer hardness different than adurometer hardness of said of said non-metallic mount flange section. 5.The non-metallic engine case inlet compression seal as recited in claim1, wherein each of said non-metallic arcuate interface section, saidnon-metallic longitudinal leg section, and said non-metallic mountflange section have a different durometer hardness.
 6. The non-metallicengine case inlet compression seal as recited in claim 5, wherein eachof said non-metallic arcuate interface section, said non-metalliclongitudinal leg section, and said non-metallic mount flange section areintegral.
 7. The non-metallic engine case inlet compression seal asrecited in claim 1, wherein each of said non-metallic arcuate interfacesection, said non-metallic longitudinal leg section, and saidnon-metallic mount flange section are integral.
 8. The non-metallicengine case inlet compression seal as recited in claim 1, wherein eachof said non-metallic arcuate interface section, said non-metalliclongitudinal leg section, and said non-metallic mount flange section aremanufactured of a silicone rubber.
 9. The non-metallic engine case inletcompression seal as recited in claim 1, wherein at least one of saidnon-metallic arcuate interface section, said non-metallic longitudinalleg section, and said non-metallic mount flange section includes fiberreinforcement.
 10. The non-metallic engine case inlet compression sealas recited in claim 9, wherein said fiber reinforcement includes anaramid material.
 11. The non-metallic engine case inlet compression sealas recited in claim 1, further comprising a fiber reinforcement thatimpregnates at least one of said non-metallic arcuate interface section,said non-metallic longitudinal leg section, and said non-metallic mountflange section.
 12. The non-metallic engine case inlet compression sealas recited in claim 1, further comprising a fiber reinforcement bondedto an outer surface of at least one of said non-metallic arcuateinterface section, said non-metallic longitudinal leg section, and saidnon-metallic mount flange section.
 13. The non-metallic engine caseinlet compression seal as recited in claim 1, wherein said non-metallicengine case inlet compression seal is configured to be positionedforward of a fan section of said gas turbine engine.
 14. Thenon-metallic engine case inlet compression seal as recited in claim 1,wherein said non-metallic engine case inlet compression seal isconfigured to extend from the outer case structure and from a forwardcircumferential edge of a fan section forward of an engine mount of thegas turbine engine.
 15. The non-metallic engine case inlet compressionseal as recited in claim 1, wherein said non-metallic arcuate interfacesection is configured to be positioned around an engine axis of the gasturbine engine.
 16. The non-metallic engine case inlet compression sealas recited in claim 1, wherein said non-metallic arcuate interfacesection is circular.
 17. The non-metallic engine case inlet compressionseal as recited in claim 1, further comprising a fiber reinforcementbonded to an outer surface of said non-metallic longitudinal leg sectionto sandwich said non-metallic leg section between said outer casestructure and said fiber reinforcement.